I have performed a 'Hard Reset' several times after cleaning the TB and MAF because of a Restricted Performance Fault. I have read just about all of the posts concerning how to do a 'Hard Reset'. I am a little confused on the correct/recommended procedure.

Some posts have you undoing both terminals and just touching the two battery cables together with no battery involved. Some have you shorting across both both terminals with the leads connected. Some have you disconnecting and touching the disconnected negative lead to the connected positive lead with the ignition switch off. Some others have the same procedure, but with the ignition in posistion 2. And several others methods remaining...

What is the correct and definitive procedure?

 

What fault codes did you get when you had the restrictive performance?

 

The Fault Code for the Throttle Body was cleared with a cleaning of the TB and MAF Sensor. That isn't the problem. I just do not know if I did a proper Hard Reset that reset the Engine Computer correctly. The method that I used was to remove the negative cable from the battery and touch it to the postive cable which was still connected to the battery (with the Ignition switch completly off), for a couple of seconds and then reconnected the negative cable. I am just trying to find out the proper and correct method for a Hard Reset.

We won't get into about reading it in the JTIS, that's another tale. I have a Vista Operating System on my PC and have yet been able to load the CD's and or load the downloads to be able to use the JTIS.

 

Bill-
What you did was correct, except you need to have the ignition fully on for the reset to effect the ECM module. (Disconnect and reconnect the battery with the ignition off, however.)

 

I read that you got the errors back after you had disconnected the battery, as then you need to focus on the issue, not reseting the ECU. Having the battery disconnected for some minutes should reset the ECU's adaptations, dont ask me how many minutes though, but would guess 30 minutes would be enough.

 

I wouldn't reccomend that one!

Avos is right, you need to pinpoint the fault and get it fixed.

 

I think that with White XKR's response, I now have the definitive answer as to the correct 'Hard Reset' method.

As far as the Resticted Performance, the Code for the TB always popped up. After cleaning both the TB and MAF Sensor and doing my 'sudio' Hard Reset (the ignition was not on) the Codes always cleared and Restricted Performance cleared out. I've had to do this twice in 8 months.

I've noticed a slight fluttering of the TB lately, when driving at moderate speed, slowing down and just about at what a normal up-shift point would be. Maybe now cleaning the TB and MAF again and a doing a proper Hard Reset (with the Ignition turned on this time) will get the ECU and air flow in sync with everything. Then the Idle will also be synched to the ECU and the shift points. Boy I'm in Heaven now, just thinking about it.

Gosh I love this car (and to all of those informative and caring individuals of this Forum, who make this Forum what it is, the best on the Web..my thanks and gratitude...)

 

The ECU will adjust itself automatically during driving although that may take several drive cycles. So sometimes it is quicker to reset the ECU after a major change (i.e. going from a very dirty to a new clean one for instance).

Sorry to be a pain, but what was the actual code you got?

 

To avos -

No problem and not a pain. It kept throwing a P1229 Code. As I said, that cleared with the TB and MAF cleaning and my 'sudo' Hard Reset.

 

The P1229 code is related to the electrical circuit for the stepper motor, and that has nothing to do with the MAF or butterfly position. Chances are that it will come back I'm afraid, maybe it is just a loosely cable connection, otherwise there could be an issue with the stepper motor.

 

If I do a hard reset on my 2004 XJR, will I have to enter some sort of code for my radio? If so, is there a way to display the code before doing the reset?

Thanks!

 

I've just had a problem with the auto gearbox on my 1998 XK8 not changing up from 2nd or 3rd and have been advised to do a hard re-set. Having read posts by BillM, AVOS and White XKR, I'm confused about the hard reset method.
My mechanic said to disconnect both battery leads and hold them in contact for about 30 seconds with ignition off, then reconnect the leads after waiting 1/2 to one hour.
BillM has been told what he did was the correct method, that is to disconnect the negative lead only and touch it on the positive lead which is still on the battery. Would this not result in a big short with lots of sparks ?
Ian

 

Both methods do the same thing. If one lead is off of a battery terminal there will be no way to short out the battery and create sparks. If it makes you feel safer, take both off, but it is really the same thing.

To reset all the modules, turn the ignition on after you disconnect the battery and then touch the wires. There should be no need to wait another 1/2 hour.

 

I have recently gotten a slew of lights. After scanning, the only two codes are P1000 and C1165 but the check engine, ABS, DSC Fault, no cruise control, and transmission lights all came on, as well.

 

I have recently gotten a slew of lights. After scanning, the only two codes are P1000 and C1165 but the check engine, ABS, DSC Fault, no cruise control, and transmission lights all came on, as well.

 

Hello Jim

Welcome to the forum. You will find a lot of knowledgeable people on here who can help you with most things.
Have you introduced yourself in the New Member section https://www.jaguarforums.com/forum/n...-intro-must-5/

What model and year do you have ?

Is this a daily driver ? as quite often the cause of several warnings at once are caused by a low/defective battery. These cars are very sensitive to battery condition!

Many have found if the battery voltage is low they get many faults listed, a recharge/replacement has quite often cured all the lights/messages.

The Code C1165 may be a fault and is:

 

Yes. I thought I had put all that info in my message, I apologize. I have a 2004 XK8. It is not a gaily driver. I just bought a brand new battery from Jaguar in Atlanta (Drove 170 miles to get a genuine battery, or a battery with a genuine label, most likely!)
A Jag mechanic there told me that the Right rear wheel sensor could possibly cause the other lights to come on. I hope to heck he is correct!

The introduction forum says the thread is now closed, by the way.

 

Indeed, you probably just paid over a $100 for a label. Top of the line Advance AP AGM battery $157. Exact physical match to the OEM one that I replaced.

Welcome to the world of North Georgia Jaguars!

 

There is a Revsam video on the sensors here